Personalized content

ABSTRACT

A media switch enables a terminal to access content by receiving a content request from a terminal for a first piece of content to be distributed over a cable system, identifying a personal channel within resources available in the cable system to distribute the first piece of content to the terminal, transmitting access information to the terminal to enable the terminal to access the first piece of content through the personal channel, and interfacing with a cable headend to provide the first piece of content on the personal channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityto U.S. application Ser. No. 14/523,158, filed Oct. 24, 2014 (nowallowed), which is a continuation of U.S. application Ser. No.11/563,663, filed Nov. 27, 2006 (now U.S. Pat. No. 8,893,196), which isa continuation of U.S. application Ser. No. 10/329,766, filed Dec. 27,2002 (abandoned). The disclosures of the above-referenced applicationsare expressly incorporated herein by reference to their entireties.

This application also incorporates by reference U.S. ProvisionalApplication No. 60/286,964, titled “Generating Multiple Data Streamsfrom a Single Content Source” and filed Apr. 30, 2001; U.S. ProvisionalApplication No. 60/343,182, titled “Duplicating Digital Streams forDigital Conferencing Using Switching” and filed Dec. 31, 2001; U.S.Provisional Application No. 60/373,329, titled “Stream Management” andfiled Apr. 18, 2002; U.S. application Ser. No. 09/893,692, titled“Generating Multiple Data Streams from a Single Content Source” andfiled Jun. 29, 2001; U.S. application Ser. No. 10/090,727, titled “ADuplicating Switch for Streaming Data Units to a Terminal” and filedMar. 6, 2002; U.S. application Ser. No. 10/134,439, titled “DuplicatingDigital Streams for Digital Conferencing Using Switching Technologies”and filed Apr. 30, 2002; and U.S. application Ser. No. 10/134,552,titled “Managing Access To Streams Hosted on Duplicating Switches” andfiled Apr. 30, 2002.

TECHNICAL FIELD

This application relates to networking.

BACKGROUND

Content may be distributed through a cable system by a cumbersomecollection of tapes, modulators, and filters that may be referred to aslegacy infrastructure. Generally, this legacy infrastructure poseschallenges to the implementation of next-generation services. Typically,the legacy infrastructure maps content analogous to television stationsignals onto the spectrum of a cable. While content may be deliveredthrough other delivery mechanisms, the legacy infrastructure representsan enormous investment, which makes a system capable of offeringnext-generation services through this legacy infrastructure desirable.

SUMMARY

In one general sense, requested content may be accessed by receiving acontent request from a terminal for a first piece of content to bedistributed over a cable system and identifying a personal channelwithin resources available in the cable system to distribute the firstpiece of content to the terminal. Access information may be transmittedto the terminal to enable the terminal to access the first piece ofcontent through the personal channel. A cable headend may be interfacedwith to provide the first piece of content on the personal channel.

Implementations may include one or more of the following features. Forexample, the personal channel may be dedicated to a single terminal andmay include a modulated channel of the cable system. The personalchannel may be accessed by tuning to a frequency and accessing datahaving a particular process identification number and transmitted at thefrequency. The first piece of content may include non-video content. Thefirst piece of content may be accessed by adding terminal addressinformation to a list of addresses supported by a broadcasting switchand/or an on-demand switch. Adding terminal address information to thelist of addresses supported by the on-demand switch may include adding aplay marker indicating the temporal location of the terminal inreceiving the first piece of content.

Implementations may include a system and program capable of achievingthe above features. Implementations also may include a sequence of stepsperformed on a media switch. The media switch may include a broadcastingswitch and an on-demand switch. Other features will be apparent from thefollowing description, including the drawings, and the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a communications system capable of using aduplicating switch to generate a stream of data units.

FIG. 2 is an exemplary component diagram of a duplicating switchsuitable for use in the communications system of FIG. 1.

FIG. 3A is an exemplary block diagram of a duplicating switch that usesmemory to store a media stream for subsequent playback.

FIG. 3B is an exemplary block diagram of a duplicating switch that usesstorage to store a media stream for subsequent playback.

FIG. 4 is a block diagram of a precoder for use in a duplicating switch.

FIG. 5 is a flow chart of a procedure for processing a received dataunit using a duplicating switch in a communications system, such as thecommunications system of FIG. 1.

FIG. 6 is a flow chart of a procedure for providing a stream of dataunits in a communications system, such as the communications system ofin FIG. 1.

FIG. 7A illustrates a duplicating switch structured and arranged tostore multiple instances of a stream of data units.

FIG. 7B illustrates a duplicating switch structured and arranged tostore multiple location identifiers.

FIG. 8 is a flow chart of a procedure for time-shifting content in acommunications system, such as the communications system of FIG. 1.

FIG. 9 is a diagram of a cable system that may be used to distributepersonalized content through a cable system.

FIG. 10 is a block diagram of a media switch that may enable access topersonalized content in a cable system.

FIG. 11 is a frequency spectrum diagram that shows how content may bemapped over a cable system.

FIG. 12 is a flow chart showing how a cable system may enable a terminalto access personalized content from a media switch through a cablesystem.

FIG. 13 is a flow chart showing how a terminal may access a particularepisode by interfacing with a media switch through a cable headend.

Like reference symbols in the various drawings indicate like elements.For brevity, several elements in the figures described below arerepresented as monolithic entities. However, as would be understood byone skilled in the art, these elements each may include numerousinterconnected computers and components designed to perform a set ofspecified operations and/or dedicated to a particular geographicalregion.

DETAILED DESCRIPTION

In general, a media switch interfaces with a terminal across a cablesystem to enable personalized access to content. When the media switchreceives a content request for a first piece of content over the cablesystem, the media switch relates the content request to one or moreavailable resources to determine if the content may be accessed from anexisting resource. If the content request may be accessed from anexisting resource, the media switch transmits access information to theterminal so that the terminal may use the existing resource to accessthe content indicated in the content request. If the content is notavailable from an existing resource, the content may be sent to theterminal over the cable system.

Also, a media switch may enable a terminal to access a personalizedchannel on a cable system. The media switch may receive a contentrequest and enable the terminal to access the requested content over thepersonalized channel. The personalized channel may be created byexchanging location information (e.g., a frequency and a processidentification number) indicative of where the terminal may access thepersonalized content on the cable system.

For illustrative purposes, FIGS. 1-8 describe a communications systemthat uses a duplicating switch to stream data units to a terminal. Forillustrative purposes, FIG. 1 depicts a communications system 100 thatimplements techniques using a duplicating switch to stream data units totwo or more terminals. Communications system 100 may be structured andarranged to include a source system 110, one or more terminals 150, andcommunication software and hardware that enable communications betweensource system 110 and terminals 150. More particularly, thecommunications system 100 typically includes the source system 110, anetwork 120, a duplicating switch 130, a network 140, and terminals 150.In actual implementations, the source system 110 generally transmits oneor more data units in a stream of data units across network 120 to oneor more duplicating switches 130. The duplicating switches store,duplicate and transmit content from the data units to one or moreterminals 150 through network 140 in an on-demand manner.

The source system 110 provides the duplicating switch 130 with a streamof one or more data units across the network 120. Typically, the sourcesystem 110 is structured and arranged to convert a media source (e.g., avideo or audio feed) into data units for transmission across the network120. The source system 110 may include a general-purpose computer havinga central processor unit (CPU), and memory/storage devices that storedata and various programs such as an operating system and one or moreapplication programs. Other implementations of the source system 110include a workstation, a server, a device, a special purpose device orcomponent, other equipment, or some combination thereof capable ofresponding to and executing instructions in a defined manner. The sourcesystem 110 also typically includes an input/output (I/O) device (e.g.,video and audio input and conversion capability), and peripheralequipment such as a display communications card or device (e.g., a modemor a network adapter) for exchanging data with the network 120.

Implementations of the source system 110 also may include a media systemthat transmits one of more pieces of media content across a network 120.For example, a source system 110 may transmit across a network to acable headend signals formatted according to European TelecommunicationsStandards Institute (ETSI), Digital Video Broadcasting (DVB), AdvancedTelevision Systems Committee (ATSC), or European Cable CommunicationsAssociation (ECCA) standards. In another implementation, a cableprovider may transmit or direct video signals to a cable headend fordistribution in a cable network.

A communications link 115 is used to communicate data between sourcesystem 110 and network 120. Communications link 115 may include wired orwireless modes of communication, such as a telephone line, a wirelessnetwork link, a cable network, or a direct connection.

The network 120 typically includes hardware and/or software capable ofenabling direct or indirect communications between the source system 110and the duplicating switch 130. The network 120 may include a directlink between the source system 110 and the duplicating switch 130, or itmay include one or more networks or subnetworks between them (notexplicitly shown). Each network or subnetwork may include, for example,a wired or wireless data pathway capable of carrying and receiving data.Examples of network 120 include the Internet, the World Wide Web, WANs(“Wide Area Network”), LANs (“Local Area Networks”), analog or digitalwired and wireless telephone networks (e.g., PSTN (“Public SwitchedTelephone Network”), ISDN (“Integrated Services Digital Network”), orxDSL (“any form of Digital Subscriber Loop”)), radio, television, cable,satellite, and/or other delivery mechanisms for carrying data.

Generally, the duplicating switch 130 is structured and arranged tostore a received stream of data units for time-shifted transmission tomore than one terminal. Implementations of the duplicating switch 130may store one or more streams of data units. For example, theduplicating switch 130 may be capable of receiving a stream of IP(“Internet Protocol”) video and storing that video for subsequenttransmission. Implementations of duplicating switch 130 also may includehardware or software capable of transmitting or receiving media feedsnot resembling a stream of data units. For example, the duplicatingswitch may include a cable headend system that is capable of receivingor transmitting signals formatted according to ETSI, DVB, ATSC, or ECCAstandards for transmission on a cable distribution system. The cableheadend system may receive a satellite broadcast feed, convert the feedinto a format suitable for storage, and thereafter convert the feed backto a different format for time-shifted transmission.

The network 140 generally includes one or more of links between theduplicating switch 130 and the terminals 150. For example, the network140 may include a direct physical link or a series of links connected byvarious pieces of network equipment. Generally, aspects of network 140may resemble aspects of network 120. For example, network 120 andnetwork 140 may share one or more hardware or software devices. Inanother example, networks 120 and 140 may use the same type of circuitsand/or equipment.

The terminal 150 may include one or more devices capable of receivingthe stream of data units transmitted by duplicating switch 130 throughnetwork 140. The terminal 150 may include a controller (not shown) thatprocesses instructions received from or generated by a softwareapplication, a program, a piece of code, a device, a computer, acomputer system, or a combination thereof, which independently orcollectively direct operations of the terminal 150. The instructions maybe embodied permanently or temporarily in any type of machine,component, equipment, storage medium, or propagated signal that iscapable of being delivered to the terminal 150 or that may reside withthe controller at the terminal 150. The terminal 150 may include ageneral-purpose computer (e.g., a personal computer) capable ofresponding to and executing instructions in a defined manner, aworkstation, a laptop, a PDA (“Personal Digital Assistant”), a wirelessphone, a component, other equipment, or some combination of these itemsthat is capable of responding to and executing instructions.

For instance, in one implementation, the terminal 150 includes one ormore information retrieval software applications a browser, a mailapplication, an instant messaging client, an Internet service providerclient, or an AOL TV (“America Online Television”) or other integratedclient) capable of receiving one or more data units. The informationretrieval applications may run on a general-purpose operating system anda hardware platform at that includes a general-purpose processor andspecialized hardware for graphics, communications and/or othercapabilities. In another implementation, terminal 150 may include awireless telephone running a micro-browser application on a reducedoperating system with general purpose and specialized hardware capableof operating in mobile environments.

In another implementation, the terminal 150 may include a simplifieddevice capable of receiving a video signal not encapsulated in atraditional data unit. For example, the duplicating switch 130 maytransmit a raw video feed formatted in accordance with ETSI, DVB, ABC,or ECCA standards for transmission directly to a cable tuner ortelevision.

FIG. 2 illustrates a duplicating switch 200 structured and arranged toreceive a stream, store content from the stream, generate data unitsfrom the stream, and transmit the generated data units as a stream. Theduplicating switch 200 generally corresponds to the duplicating switch130 in FIG. 1. The duplicating switch 200 generally includes a storagesystem 210 for storing the stream of data units, a high speedinterconnect 220 between the various subsystems in the duplicatingswitch 200, a switching engine 230 for modifying and transmitting thestream of data units to two or more clients, a first communicationsinterface 240 for receiving a stream of data units from a source system,and a second communications interface 250 for transmitting a stream ofdata units to two or more clients.

The storage system 210 enables the duplicating switch 200 to store atleast the content portion of the data unit. The storage system 210 maybe volatile or nonvolatile and may include memory (e.g., RAM) and/orstorage (e.g., HDDS). Implementations of storage system 210 may includea hard disk drive or a more portable media, e.g., a compact disk, a tapedrive, or an optical memory device. Implementations also may includecombinations of memory and storage.

The high speed interconnect 220 generally refers to a device thatconnects a component of the duplicating switch 200 with other elementsof the duplicating switch 200, Examples of the high speed interconnect220 may include, but are not limited to, SCSI (“Small Computer SerialInterface”), Fibre Channel, UTOPIA (“Universal Test and Operations PHYinterface for ATM (“Asynchronous Transfer Mode”)), Infiniband, and otherprotocols and connection methods. The high speed interconnect mayinclude physical, logical, timing and electrical connections andstandards as well as protocols that enable these high speedinterconnects to exchange data.

Generally, a switching engine 230 includes a device that performsnetwork operations in hardware (e.g., a chip or part of chip). In someimplementations, the switching engine 230 may include an ASIC(“Application Specific Integrated Circuit”) implementing networkoperations logic directly on a chip (e.g., logical gates fabricated on asilicon wafer then manufactured into a chip). For example, an ASIC chipmay include a logical gate structure implemented in silicon andconfigured to receive a packet and filter based on examining an IPaddress.

Implementations of the switching engine 230 may include a FPGA (“FieldProgrammable Gate Array”). An FPGA generally is defined as a chipfabricated to allow third parties to implement a variety of logicaldesigns (e.g., group of gates) on the chip. For example, one designermay load a design that replaces the IP address of received IP packetswith a different IP address, Another example may include a design thatperforms segmentation and reassembly of IP packets as they are modifiedduring transmission of the IP packet through different networks.

Implementations of the switching engine 230 also may include a networkprocessor. A network processor generally is defined as a chip that,among other features, allows software to specify which networkoperations should be performed. One example of a network processor mayinclude several interconnected RISC (“Reduced Instruction Set Computer”)processors fabricated in a network processor chip. The network processorchip may implement on some of the RISC processors software that changesan IP address of an IP packet. Other RISC processors in the networkprocessor may implement software that controls which terminals receivean IP stream.

The switching engine 230 may include a precoder (not shown) that isstructured and arranged to receive a data unit, extract a content piecefrom the payload portion of the data unit, determine where the contentpiece will be stored, and store the content piece in a structured mannerso that retrieval (e.g., playback) involves retrieving neighboringcontent pieces, packaging data units around the content pieces, andtransmitting the data units to one or more requestors. This process willbe described further with respect to FIG. 4.

The first communications interface 240 generally is structured andarranged to receive a stream of data units from a device such as thesource system 110. Implementations of the communications interface mayinclude a LAN or WAN interface with the ability to direct the data unitsto one or more locations in the duplicating switch 200, using, forexample, the high speed interconnect 220. Implementations also mayinclude other forms of transmitting a media signal, includingtransmission according to ETSI, DVB, ATSC, or ECCA standards.

The second communications interface 250 generally is structured andarranged to transmit a stream of data units from the memory system 210to one or more devices that generally correspond with recipients, suchas terminal 150 described with respect to FIG. 1. Implementations of thesecond communications interface 250 may include a LAN or WAN interfacewith the ability to direct the data units to one or more locations inthe duplicating switch 200 using, for example, the high speedinterconnect 220. Implementations also may include other forms ortransmitting a media signal other than by IP networking. In addition,the second communications interface 250 is not limited to the same typeof format as the first communications interface 240, though theinterfaces may include the same format and even the same physicalinterface. For example, the first communications interface 240 mayinclude a POS (“Packet-over-SONET”) interface while the secondcommunications interface 250 may include some form of Ethernet (e.g.,100-Base-T or Gigabit Ethernet).

FIG. 3A provides an exemplary block diagram of a duplicating switch(e.g., duplicating switch 130 in FIG. 1) with a memory implementation.The duplicating switch 300A includes a RAM array 320A, a switchingengine 330A and a network interface 340A.

The RAM array 320A may include one or more RAM memory banks structuredand arranged to store one or more pieces of content. The RAM array 320Amay store just a portion of the stream of data units. For example, aprovider streaming out a movie may store one portion of the movie forseveral users to watch at one time. The RAM array 320A may store awindow (e.g., a ten-minute window) of the movie that a user may use totime-shift the movie (e.g., pause, stop playing, or rewind) whilestaying current with the movie being broadcast.

Within the RAM array 320A, there may be location identifiers to monitoror indicate which content piece to package and/or transmit to aterminal. For example, an OSP (“Online Service Provider”) may schedule astream of data units to be transmitted to terminals at a certain time.In one example, the duplicating switch loads a portion of the stream ofdata units indicated by the location identifier to the RAM array 320A.In this example, the duplicating switch may use one or more pointers toindicate which data units (e.g., frames) should be transmitted to whichuser. In another example, an on-demand system may load a larger portionof the data units to memory and may use a first pointer to transmit onestream of data units and a second pointer to transmit a second stream ofdata units simultaneously or otherwise.

The switching engine 330A is structured and arranged to manage thecontent being stored in and retrieved from the RAM array 320A. Aspectsof the switching engine 330A generally correspond to aspects of theswitching engine 230 in FIG. 2. The switching engine 330A generallyloads and retrieves content to/from the RAM array 320A. Examples ofcontent that may be loaded and retrieved by switching engine 330Ainclude content pieces without wrappers (e.g., OSI wrappers), such asdatagrams having MPEG (“Motion Picture Experts Group”) I, P, and Bframes removed, video frames and differential checksum values thatdescribe frame-to-frame changes, and frames with one or more addedwrappers (e.g., a layer 4 datagram). In one implementation, theswitching engine 330A may implement a system of pointers designed tomonitor where in time or sequence number the terminals are with respectto the available stored content. The switching engine 330A may include adevice, a program, a software controller, or another system or device incombination with the above. In another implementation, the switchingengine 330A may manage overall system utilization and refuse subsequentrequests for services or attempt to serve more than one terminal fromone stream of data units. The network interface 340A is designed totransmit and receive a stream of data units and generally corresponds tothe first communications interface 240 and second communicationsinterface 250 described in FIG. 2.

FIG. 3B provides another exemplary block diagram of a duplicating switch300B with a storage implementation. The duplicating switch 300B includesa stream platform 310B, a switching engine 330B, and a network interface340B.

The stream platform 310B is structured and arranged to store contentfrom within a stream of data units. The stream platform 310B includes ahard disk drive 312B (or a tape drive or other magnetic memory) andoptical memory 316B. Generally, the stream platform 310B includes memorycomponents with low bandwidth performance but high capacities. Forexample, storage may include solid-state-memory (not shown) that isslower than solid-state memory used in other applications. Typically,because of the greater storage available with less bandwidth, the streamplatform 310B will store a larger portion of a stream (e.g., a movie),but will limit access to fewer simultaneous streams absent RAM or othercache interfaces.

Implementations of the storage platform 310B may include the diskstorage 312B with a RAM interface to the switching engine 330B. Forexample, the duplicating switch may include a RAM bank and disk storage.Content pieces may be loaded to the disk storage such that the contentpieces are retrieved in the order that they are transmitted. As thecontent pieces are being retrieved, they are loaded to the RAM bank. Thehigher throughput performance of the RAM banks may enable more terminalsto access the same content piece. Terminals accessing the stream of dataunits may use a pointer to the content pieces in the RAM bank to monitorand load the data units they need in the stream of data units.

The switching engine 330B is structured and arranged to manage thecontent being stored and retrieved in the stream platform 310B. Theswitching engine 330B generally corresponds to the switching engine 330Adescribed with respect to FIG. 3A. The network interface 340B isdesigned to transmit and receive a stream of data units and generallycorresponds to the first communications interface 240 and secondcommunications interface 250 described with respect to FIG. 2.

The RAM-based and storage-based systems described with respect to FIGS.3A and 3B illustrate implementations that are designed to account forcommon limitations of existing memory and storage systems (e.g.,solid-state RAM offers high throughput but less storage while harddrives and optical memory offer higher storage but less throughput).However, implementations are not limited to those shown, nor are memoryor storage devices necessarily subject to these constraints. Forexample, a disk drive may be used to implement a system managingmultiple pointers and may offer higher bandwidth, while solid-statememory may offer higher density storage than the disk drive storage.

FIG. 4 shows an example of a duplicating switch 400 with precoderfunctionality. The duplicating switch 400 generally corresponds to theduplicating switch 130 of FIG. 1. The duplicating switch 400 includes adata unit interface 410, a content extraction system 420, a contentarrangement system 440, and a content store 450.

The data unit interface 410 generally is structured and arranged tointerface with a network to transmit and receive a data unit from thecontent store 440. Generally the functionality of the data unitinterface 410 corresponds to the functionality of the firstcommunications interface 240 and the second communications interface 250of FIG. 2. Data unit interface 410 also may be configured to segment andreassemble a data unit that has been separated during transmission, orto handle unconventional data units. For example, the data unitinterface 410 may be configured to transmit/receive one or more mediaframes (e.g., frames formatted according to one of the ETSI, DVB, ATSC,or ECCA standards). In one instance, if the duplicating switch 400receives an analog signal, the data unit interface 410 may convert thesignal to a recognized format that the frame or content piece may store.

The content extraction system 420 is structured and arranged to remove adata unit wrapper that is added around content for transmission. Forexample, the content extraction system 420 may remove one or more bitsassociated with OSI (“Open Systems Interconnect”) informationencapsulated along with the content for transmission. The contentextraction system 420 also is capable of adding the wrapper when thedata is retrieved from the content store 450 for subsequenttransmission. For example, the content extraction system 420 may removewrapper information when storing a stream of data units in the contentstore 450 and may add a different wrapper when transmitting the streamof data units from the content store 450.

The content arranger 440 is structured and arranged to direct storageand retrieval of the content information such that the contentinformation may be retrieved in a determinate manner. For example, thecontent may be arranged so that the addressing information may beupdated in predictable increments. In another example, the content maybe arranged such that the difference between frames of content may becalculated by analyzing an associated checksum that then may be stored.

Determining where a content piece may be stored and storing the contentpiece may include using hard disk drive constraints to store the contentpiece. For example, the content store 450 (e.g., hard drive) may storethe content pieces such that the same “read” or data retrieval willretrieve related content pieces that are frequently transmitted in closeproximity to one another (e.g., adjacent frames in a movie or adjacentI, P, and B MPEG frames).

Determining where a content piece may be stored and storing the contentpiece may include using solid-state storage (e.g., various forms of RAM)to store the content piece. For example, the solid-state storage maystore all or a portion of the stream in an array of RAM memory. If aportion of the RAM memory is used to store the content piece, the RAMmay load a certain window of content for transmission to one or moreterminals. In some implementations, the duplicating switch may storemore than one instance of the stream of data units in the array of RAM.

The content store 450 is structured and arranged to store content piecesor frames. As described above with respect to the content arranger 440,the content is generally structured and arranged to be retrieved in amanner enabling transmission of related content pieces to one or moreterminals. The content store 450 generally corresponds to the memorysystem 210 of FIG. 2, the RAM array 320A of FIG. 3A, and the storageplatform 310B of FIG. 3B.

FIG. 5 illustrates a procedure 500 for storing and transmitting a dataunit using a duplicating switch. In general, the procedure 500 may beperformed using one of the duplicating switches described with respectto FIGS. 1-4.

Initially, the duplicating switch receives a data unit (step 505) andselects the content piece from the data unit (step 510). Typically,selecting the content piece of the data unit (step 510) involvesidentifying fields or portions of the data unit that correspond to thecontent, and removing some or all aspects not related to the content.For example, a duplicating switch may remove one or more layers of anOSI (“Open Systems Interconnection”) header and store the remainder ofthe data unit as the content piece. In another example, selecting thecontent may include creating or modifying location identifiers toidentify which portion of the data unit should be stored when the dataunit is loaded to memory.

Selecting the content (step 510) may include enabling one or moreportions of other aspects of the data unit to be retained with thecontent. For example, one or more fields of the OSI header may bepreserved and stored as content.

Implementations may include using a pre-coder to modify or adjust thecontent for storage. For example, the pre-coder may compress the contentso that less bandwidth is consumed during transmission. In anotherexample, the pre-coder may calculate a checksum or shortcut describingintra-content differences. This checksum or shortcut may be stored inplace of storing some of the content pieces.

The duplicating switch determines the location in the memory system inwhich to store the content piece (step 520). Typically, the location forstorage of the content piece is selected so that related content piecesmay be retrieved in related operations. Examples of related content mayinclude sequential frames in a video and/or content in a time slice. Theduplicating switch then stores the content piece in the determinedlocation (step 530).

At some later time, the duplicating switch receives a request for acontent piece (step 540). Receiving a request for a content piece mayinclude receiving a user (e.g., terminal 150 in FIG. 1) request displayof a video stream on the user's home computer. Implementations also mayinclude having other devices request the content piece. For example, acable modem acting as a set top box may request a content piece fordisplay to a television.

Implementations also may include having a request originate from asource other than the intended destination. For example, a cable systemadministrator may generate a request for the content piece on behalf ofone or more subscribers.

The duplicating switch 130 determines which content piece has beenrequested (step 550). The requestor may designate a content piece tosend. For example, a terminal may keep track of which content has beenreceived, and may generate a request for one or more pieces of content(e.g., frame number 100 is missing). Implementations also may includehaving the duplicating switch track which content piece is required. Forexample, a duplicating switch may attempt to transmit the same contentpiece to several users.

The duplicating switch 130 determines where the content piece is located(step 560). To do so, the duplicating switch may use the locationidentifiers described with respect to FIGS. 2 and 3. Otherimplementations may employ a file and/or an archiving system maintainedto manage access to content pieces.

The duplicating switch 130 retrieves the content piece (step 570). Theduplicating switch may do so by reading a memory location specified by alocation identifier. Other implementations may include retrievingmultiple pieces of content information (e.g., reading a sector on adisk).

The duplicating switch 130 packages the content piece in a data unit(step 580). For example, the duplicating switch may add one or morelayers of OSI information (e.g., addressing information).Implementations where one or more aspects of the data unit other thancontent are stored with the content piece may include modifying one ormore parameters in those fields. For example, if an Internet Protocolpacket is stored, the destination address may be modified to theaddresses of requesting users.

Finally, the duplicating switch transmits the data unit to one or moreterminals (step 590). The data unit may be transmitted in formats otherthan IP addressing. For example, transmitting the data unit may includetransmitting an on-demand channel over a network.

Referring to FIG. 6, the function of a communications system 600 willnow be described. Communications system 600 generally includes a sourcesystem 602, a manager 604, a duplicating switch 606, and terminals 608and 610. In general, the source system 602 corresponds to the sourcesystem 110 of FIG. 1, duplicating switch. 606 corresponds to duplicatingswitch 130 in FIG. 1, and terminals 608 and 610 correspond to terminals150 of FIG. 1. The manager 604 may include a cable system operator, anOSP, a content provider, or an entity capable of providing instructionsor direction to the duplicating switch 606.

As shown, the source system 602 generates a stream of data units (step613). The source system 602 transmits the stream of data units to theduplicating switch 606 (step 616).

The duplicating switch 606 receives the stream of data units (step 625).The duplicating switch 606 then stores at least the content pieces fromthe stream of data units (step 627).

The stream may be transmitted in a variety of ways. In someimplementations, the manager 604 waits for a condition to occur (step618). For example, the manager may be a scheduler that is programmed todirect a duplicating switch “broadcast.” When the condition occurs (step620), the manager 604 transmits a request to the duplicating switch 606to transmit the stream of data units (step 623).

Alternatively, a terminal 608 may generate a request for a stream (step633). For example, the terminal 608 may generate a request to view aparticular video stream. The duplicating switch 606 receives the request(step 630).

In an implementation generally corresponding to the system describedwith respect to FIG. 3B, the duplicating switch 606 may load one or morecontent pieces into fast memory (e.g., RAM) (step 631). For example, theduplicating switch 606 may determine that there is inadequate bandwidthto the existing storage of the content and may load frequently-accessedcontent pieces to the faster memory to increase capacity.

Regardless of the mechanism used to indicate when to transmit the streamof data units to a terminal, the duplicating switch 606 may transmit thestream of data units to two or more terminals 608, 610 (step 636). Insome implementations, a terminal receives a stream that has beenbroadcast or otherwise automatically transmitted to the stream recipientwithout requesting the stream of data units. In either case, terminals608 and 610 receive the stream of data units (step 640 and 640A).Depending on the implementation, a different “stack” of content piecesmay be loaded into memory to support terminal 610.

In some implementations, the terminal 608 may generate and transmit apause message (step 645). For example, a terminal may wish to “pause” avideo on-demand stream and return to the stream at a later point. Whenthe duplicating switch 606 receives the pause message (step 650), theduplicating switch 606 pauses transmitting to the terminal 608 (step655). The duplicating switch 606 may still transmit a stream of dataunits to terminal 610 (not shown). The pause message may be implementedin a variety of ways. For example, terminal 608 may keep track of whichdata units have been received and resume where it left off by generatingand transmitting a resume message (step 660). Another example mayinclude having the terminal 608 transmit a stop message and theduplicating switch 606 keep track of where to resume when the transmitresume message is received (step 660).

If and when the duplicating switch 606 receives the resume message (step665), the duplicating switch 606 transmits the stream of data units 670to the terminal (step 670). The terminal 608 then receives the stream ofdata units (step 675).

FIG. 7A depicts a duplicating switch 700A structured and arranged tostore multiple instances of the stream of data units. The duplicatingswitch 700A transmits two streams of data units, stream A and stream A1.Stream A occupies memory storage 710A in the memory bank, while streamA1 occupies memory storage 720A in the memory bank. In oneimplementation, a first pointer 715A to the memory storage 710Aindicates which content piece, relative to other content pieces, shouldbe encapsulated as a data unit and transmitted to a terminal requestingStream A. As mentioned previously, implementations may include storing aportion of the content pieces in the memory bank. For example, ifproblematic network conditions prevent a terminal from receiving some ofthe stream of data units, the terminal may not receive some of thecontent pieces and may experience gaps in receiving the stream of dataunits (e.g., missing time in a movie).

A second pointer 725A to the memory storage 720A indicates whichportions of content pieces encapsulated in a stream of data units arebeing transmitted to several terminals. One or more terminals wishing toreceive one or more data units in the stream of data units receive thecontent piece corresponding to the second pointer 725A, which iscontinuously advanced to the next content piece. In someimplementations, the second pointer 725A may advance several contentpieces and encapsulate more than one content piece in a data unit.

FIG. 7B depicts a duplicating switch 700B structured and arranged tostore multiple location identifiers. In this example, duplicating switch700B includes five content pieces in stream A: A1 710, A2 720, A3 730,A4 740, and A5 750. Duplicating switch 700B also includes an area ofmemory allocated for an expected content piece A6 760.

In one example, the duplicating switch 700B enables each of terminals T,U and V to receive its own stream of data units. Each of the terminalsmanages a location identifier (e.g., pointer) to direct the duplicatingswitch to select the appropriate content piece to be transmitted. Forexample, terminals T, U, and V may begin by requesting content piece A1710 simultaneously.

After some content pieces have been transmitted, and as shown in FIG.7B, the location identifier 725 for terminal T may be referencingcontent piece A2 720, while the location identifier 742 and the locationidentifier 744 for terminals U and V are referencing content piece A4740 that corresponds to a different time-shift than content piece A2.This offset may have occurred because, for example, terminal T pausedreceipt of the stream of data units, and is now receiving content piecesthat are delayed relative to those received by terminals U and V.

In another example, duplicating switch 700B includes five content piecesin stream B: B1 770, B2 771, B3 772, B4 773, and B5 780. Duplicatingswitch 700B also includes an area of memory allocated for an expectedcontent piece B6 790. In one implementation, stream B may be part of thesame stream of data units as stream A, but may correspond to a differentportion of the stream of data units. For example, stream A may be a“video” stream 40 minutes into a video stream while stream B is fiveminutes into the same video stream. In another example, stream B may beidentical to stream A but was added to implement better systemperformance. In yet another example, stream A and stream B may representcompletely different video streams (e.g., two different televisionchannels).

FIG. 8 illustrates a procedure 800 for implementing a “Pause” functionon a duplicating switch, such as the duplicating switches described withrespect to FIGS. 1-7. Initially, the duplicating switch receives astream of data units (step 810) and stores content pieces from thestream of data units (step 820). With the content stored and ready fortransmission, the duplicating switch waits to receive a request to playthe stream of data units (step 830). Though the duplicating switch maywait for a request-to-play message, in some implementations, theduplicating switch may begin to transmit (e.g., play) upon receipt ofthe stream. In this configuration, the content might only be stored whena user requests pausing of the stream.

In an optional implementation, the duplicating switch may load thestream (content pieces) to fast memory (step 840). This generallycorresponds to loading the stream to fast memory as described withrespect to FIG. 6.

The duplicating switch transmits the stream of data units (step 850).While transmitting the stream, the duplicating switch 130 may receive apause request (step 860). If the duplicating switch 130 receives a pauserequest, the duplicating switch stops transmitting the stream of dataunits to the terminal (step 865). With the stream of data units paused,the duplicating switch 130 may wait to receive a play request (step870).

If the play request is received, the duplicating switch 130 continues totransmit the stream of data units where the terminal left off (step880). If not, the duplicating switch 130 waits for the resume request.When the terminal resumes receiving the stream of data units, theduplicating switch checks for a new pause request (step 860).

If the duplicating switch 130 does not receive a pause request, theduplicating switch may receive a stop request or reach the end of thestream (step 885). If the stop request is received or the end of thestream of data units is reached, the duplicating switch ceasestransmitting (step 890). If not, the duplicating switch 130 continuestransmitting and returns to waiting for a pause request (step 860).

Referring to FIG. 9, a cable system 900 enables a media switch 930 totransmit content (e.g., video) to a terminal 950. The media switch 930is connected through a network 935 to cable headend gear 940, which isconnected through a network 945 to the terminal 950. Aspects of cablesystem 900 generally relate to aspects of the communications systemsdescribed previously with respect to FIGS. 1-8. However, FIG. 9illustrates how aspects of the duplicating switch described previouslymay be used in a media switch in the context of a cable system.Specifically, cable system 900 may enable access to terminal-specificcontent through a cable system, for example, by mapping content ontofrequency/process identification numbers used by the cable system andexchanging the access information with the terminal.

Generally, media switch 930 includes aspects of a duplicating switch,such as the switch 130 illustrated in various of FIGS. 1-8, which isconfigured to interface with the cable headend 940 and the terminal 950to enable access to content. Typically, media switch 930 includescommunications interfaces that may be used to send and receive content.For example, the media switch 930 may receive content from an upstreamnode (e.g., a source system 110). This received content may betransmitted to other devices (e.g., PCs (not shown in FIG. 9), cableheadends 940, and terminals 950). The received content also may bestored to enable on-demand access to the content.

The media switch 930 is not limited to video content. For example, themedia switch 930 may include audio content for cable-based radiostations, text and imaging content for displays and slide shows, andoverlay content to be displayed with video content and/or as analternative to the video programming.

The network 935 may include one or more communications paths between themedia switch 930 and the cable headend 940. Generally, aspects of thenetwork 935 may relate to aspects of the networks 120 and 140 describedpreviously. However, network 935 may be configured to address one ormore issues arising in the context of distributing content to a cableheadend 940. For example, network 935 may use certain transmissionparameters (e.g., to control jitter, quality of service, and/or complywith reception requirements of the cable headend 940). Other aspectsrelating to interfacing with a cable headend 940 may includechannelization control and/or scheduling. For example, a piece ofcontent may be configured as an IP stream so that minimal processing isrequired to map the IP stream into the feed transmitted over the cablesystem.

Cable headend 940 typically is structured and arranged to receive astream of content from the media switch 930 and to transmit the contentacross the network 945 to the terminal 950. This may involve mappingreceived streams of content to a system of channels used by a set topbox. For example, in the case of QAM (Quadrature Amplitude Modulation),the content may be mapped to a frequency/PID (“Process IdentificationNumber”) pair. A set-top box accessing the cable system may know that aparticular pair (e.g., 1/112) corresponds to a particular channel (e.g.,channel 2), while another pair (e.g., 3/115) corresponds to anotherchannel (e.g., channel 45). In this manner, the appearance of “channels”may be maintained for users, independent of the underlying cable system.

Typically, network 945 includes part of a cable system from which theterminal 950 may access a cable signal. For example, the cable signalmay distribute 100 channels for a consumer to access. The cable systemmay include one-way and two-way communications. To illustrate, a portionof the available bandwidth may be allocated for high-speed Internetaccess to enable a terminal to send and receive data. In anotherillustration, the channel may include a one-way video signal beingdistributed to set-top boxes.

Typically, the terminal 950 enables a consumer to access a cable system(e.g., via network 945) to receive content. Examples of the terminal 950may include a set-top system, a tuner, a personal computer, and anInternet access device. The terminal 950 may include a proxy and one ormore other access devices behind the proxy. For example, a consumer mayhave a tuner system that demultiplexes a signal and sends contentsignals to one or more home appliances (e.g., a television).

Generally, the terminal 950 is configured to select a channel of contentwithin the overall group of channels. For example, a terminal 950 mayselect a particular frequency/PID pair (e.g., 1/112) to access aparticular television channel (e.g., channel 2). The tuner 950 generallyis able to exchange data with one or more other systems (e.g., mediaswitch 930 or cable headend 940).

One example of the communications capability may include accessing thecommunications link 960. The communications link 960 may use the samecommunications channel as the content being distributed (e.g., in-bandcommunications), or it may include out-of-band communications. Forexample, an in-band communications link 960 may include having theterminal 950 use a cable channel dedicated to Internet access totransmit content requests to the media switch 930 and/or the cableheadend 940, for example, through networks 935 and 945. An example of anout-of-band communications link may include a modem that accesses aphone line and/or a wireless modem designed to access a wireless network(e.g., a TDMA (“Time Division Multiple Access”) or 802.11 (b) network).

The communications link 960 may interface through one or moreintermediate devices to access the other systems. For example, the cableheadend 940 may act as a proxy for communications from the terminal 950to the media switch 930. The cable headend 940 may receivecommunications formatted in a first protocol and convert them to asecond protocol for transmission on the network 935.

FIG. 10 is a block diagram of media switch 930. Media switch 930includes a first communications interface 1010, a broadcasting switch1020, an on-demand switch 1030, a switch controller 1040, and a secondcommunications interface 1050. In general, the media switch 930 isconfigured to access content from a content source and to enable one ormore terminals to access the content in real-time and/or on-demand.

Generally, the first communications interface 1010 accesses one or moresources of content for the media switch 930. In one example, the firstcommunications interface 1010 is a software controller that pullscontent from a source system. In another example, the firstcommunications interface 1010 is configured to receive pushed content.

The first communications interface 1010 may include a data networkinterface (e.g., an Ethernet interface), or it may includemedia-oriented interfaces. For example, the interface may be configuredto receive MPEG32 content from a satellite.

The broadcasting switch 1020 typically is configured to enable real-timeor near real-time access to media content. For example, the broadcastingswitch 1020 may receive a feed and may transmit the content to severaldevices. In general, the label “broadcast” refers to the real timenature of the content, rather than the ability of the content to be seenby more than one terminal (e.g., an IP multicast). However, depending onthe configuration of the cable system, the broadcast content may be seenby more than one user.

The on-demand switch 1030 enables on-demand access to stored content.For example, premium content involving additional costs may be stored toa disk drive. Access to this content on the disk drive may be managedthrough a collection of location identifiers that each indicate thelocation at which one terminal receives the content. If a user wishes topause a feed, the location identifier may be stopped at its presentlocation so that the content may be subsequently accessed at the samepoint when the user wishes to resume.

Typically, the switch controller 1040 may be used to control the systemsin the media switch 930. For example, the switch controller 1040 mayinclude a scheduling program to coordinate timely delivery of content toother devices, such as, for example, the cable headend 940. Thisscheduling program may enable stored on-demand content to be sent out as“live content” by coordinating a nearly simultaneous delivery of storedcontent to the cable headend 940. Thus, the stored content can be mappedinto predefined channels so that a user can time in to the advertisedchannel at the advertised time. Similar scheduling also may be performedusing the broadcasting switch 1020.

The switch controller 1040 also may interface with one or moreoff-device systems. For example, the switch controller 1040 mayinterface with a terminal 950 to receive content requests. In anotherexample, the switch controller 1040 may interface with a cable headend940 to control frequency/PID mappings.

Typically, the second communications interface 1050 exchanges data witha cable headend 940 and/or terminal 950. For example, the media switch930 may use the second communications interface 1050 to transmit contentto cable headend 940 for distribution to a terminal 950. In anotherexample, the second communications interface 1050 may receive contentrequests from the terminal 950.

Referring to FIG. 11, frequency spectrum diagram 1100 shows thefrequency/bandwidth allocation structure that may be used in a cablesystem (e.g., network 945). A typical cable system may use multiplefrequencies and PIDs within each frequency. However, for exemplarypurposes, three frequency base bands are shown, Frequency Band (FB)1110, FB 1130, and FB 1150. Typically, each frequency band represents abase band around which multiple channels/PIDs within the frequency areused. For example, several frequencies may be modulated around a higherbase band frequency. In another example, several channels may betime-division multiplexed around the base band frequency. In yet anotherexample, each channel may be Quadrature Amplitude Multiplexed around abase band signal. Additionally, there is typically a guard band (notshown) that separates adjacent signals.

FB 1130 illustrates how 4 PIDs (e.g., channels) may be multiplexed intothe one frequency band. FB 1130 includes PIDs 1131, 1132, 1133, and1134. Each of these PIDs may be a channel accessible by severalterminals or a personalized channel. The channels may be dynamicallyaccessible and/or programmable. For example, implementing a personalizedchannel may involve allocating a frequency/PID pair for each terminal.The media switch 930 then coordinates content requests with the cableheadend to ensure that the required content is transmitted to the cableheadend for mapping onto the specified frequency/PID. In anotherexample, a terminal 950 may receive a message indicating whichfrequency/PID pair will be used to transmit the requested content. Thesefrequency/PID pairs may be reused and shared, depending on the state andconfiguration of the network 945.

Referring to FIG. 12, a flow chart 1200 shows how a media switch 930 mayinterface with a terminal 950 to enable the terminal 950 to requestcontent. Initially, the terminal 950 determines a content requirement(step 1210). Determining a content requirement may include perceiving auser selection of content, explicitly, implicitly or intentionally. Forinstance, in a cable television environment, determining a contentrequirement may include having a consumer interface with an automatedprogramming guide showing programming content and available times forthe programming content. In another example, determining a contentrequirement may include selecting a piece of on-demand content from alist of on demand offerings. In yet another example, determining acontent requirement may include changing a channel to which the user istuned. The appearance of changing channels may involve interfacingthrough an intermediary interface so that the user cycles throughpreferred channels in order of preference. The preferred channels listmay be generated in a seamless manner without requiring userintervention.

With the content requirement, the terminal 950 transmits a contentrequest (step 1220). Transmitting a content request may be performedthrough in-band or out-of-band communications. The media switch 930receives the content request (step 1230).

The media switch 930 accesses content (step 1235). Accessing content mayinclude requesting content from an on-demand device, a broadcastingswitch, and/or an on-demand switch. Accessing content may includeloading the content to the broadcasting switch and/or theon-demand-switch. If the first piece of content has been loaded toeither of these switches, accessing content may include adding terminaladdress information to a list of addresses on the duplicating switch.For example, if the terminal requests live content being duplicated on abroadcasting switch, an IP address related to the terminal may be addedto the list of devices to which the broadcasting switch is sendingcontent. For example, the broadcasting switch may receive a virtual IPaddress for a cable headend interface that maps the streamed content toa personal channel over the cable system.

Accessing content also may include receiving content automatically(e.g., from a satellite or an analog feed), or in response to ascheduled pushing program designed to ensure timely delivery of thecontent.

The media switch 930 identifies a personal channel (step 1240).Identifying a personal channel generally includes identifying a resource(e.g., a modulated channel) within the cable system available todistribute the content to the terminal. The personal channel may bededicated to a single terminal. For example, identifying the personalchannel may include accessing a database of modulated channels (e.g., afrequency/PID pair) not being used and allocating one of the availablechannels for exclusive use by the requesting terminal. In anotherexample, the personal channel may be identified in advance andidentifying the personal channel may include determining that thepersonal channel exists and is being used by the requesting terminal.

Identifying a personal channel (step 1240) may include identifyingaccess information that enables the terminal 950 to access the personalchannel. The access information may include parameters describing thefrequency and the process identification number within the frequency. Inanother example, the access information may include a label that servesas a proxy for this information. For example, the terminal 950 mayinclude a mapping function that converts a label into the frequency andthe process identification number.

In any event, the media switch 930 transmits the access information tothe terminal 930 (step 1250), which receives the access information(step 1260).

The media switch 930 interfaces with a cable headend 940 (step 1270).Typically, interfacing a cable headend 940 includes enabling contentsent by the media switch 930 to be distributed by the cable headend 940on the personal channel. The cable headend 940 interfaces with the mediaswitch 930 (step 1280). One example of interfacing may includedetermining a mapping of content into a personal channel as afrequency/PID pair. In another example, interfacing may includeaccessing a configuration database describing the frequency/contentmapping. In yet another example, interfacing between the media switch930 and the cable headend 940 may include managing reception of an IPstream or other transport stream with the requested content from themedia switch 930 to the cable headend 940. Although an exemplary IPstream has been described, the cable system is not limited to using IPto distribute requested content.

Interfacing with the cable headend 940 may be performed in conjunctionwith other operations that have been described. For example, the cableheadend 940 may determine what frequency/PID pairs are available, mapthe requested content to a selected pair in the available pairs, andtransmit those parameters to the media switch 930 for transmission tothe terminal 950. In another example, the media switch 930 also managesthe frequency/PID mappings and directs the cable headend 940 to map thecontent to the designated frequency/PID.

In any event, the terminal receives the content by referencing thelocation indicated in the access information (step 1290). In the examplewhere the personal channel is already created and being used, accessingcontent information may include receiving the newly requested content onthe personal channel already being used.

Although the operations described are described in a sequential order,the operations described above may be performed in parallel and/or adifferent order. For example, the content may be accessed before thecontent request is received. Similarly, the media switch 930 mayinterface with the cable headend 940 before or in conjunction withaccessing content. Other sequences and combinations may be used.

FIG. 13 is an exemplary flow chart 1300 showing a terminal accessingpersonalized content through a media switch. Generally, the systemsshown in FIG. 13 relate to the systems described previously. Forexample, the media switch 930, the cable headend 940 and the terminal950 may relate to the media switch 930, the cable headend 940, and theterminal 950 described with respect to FIGS. 9-12. However, flow chart1300 illustrates how a terminal accesses a particular televisionepisode.

Initially, the terminal 950 determines episode A of television show Bshould be accessed (step 1310). For example, the user may have missedthe scheduled transmission of episode A and elect to watch the missedepisode. Alternatively, the user may enjoy the particular series, or beparticipating in a distance-learning course.

The terminal 950 transmits a request for episode A to the media switch930 (step 1320). The media switch 930 receives the request, eitherthrough the cable system (e.g., cable headend 940), or through alternatechannels (not shown) (step 1330). The media switch accesses episode A(step 1335). In one instance, accessing episode A involves accessing adata store local to the media switch 930 that is used to store recentlybroadcast content. Alternatively, the user associated with terminal 950may be allocated a personal data store on the media switch 930. The usermay actively manage this personalized data store on the media switch930, or the media switch administrator may proactively manage content onthe user's behalf. For example, the media switch may determine that theuser routinely requests television show B and ensure that severalepisodes from television show B are stored and available for the user toaccess.

The media switch 930 identifies a personal channel so that the terminal950 may access episode A (step 1340). For example, the media switchdetermines that frequency X and PID Y may be used to transmit episode A.Identifying the personal channel may include scheduling the transmissionso that the transmission does not conflict with other scheduledtransmissions. For example, if the media switch 930 determines that, dueto terminal 950 “pausing” the stream, episode A would overlap asubsequent transmission on frequency X and PID Y, the overlappingconflict may be resolved. In one case, the time-shifting ability of thecurrent transmission may be limited. For example, the user may beprecluded from pausing episode A. The media switch 930 also mayreschedule the subsequent transmission to a different frequency andchannel. Other options may include, but are not limited to, cancelingeither the present or the subsequent transmission.

The media switch 930 instructs the terminal to access frequency X andPID Y to access the personal channel (step 1350). The terminal 950receives the access information (step 1360). The media switch 930interfaces with the media switch 930 to transmit episode A on frequencyX and PID Y (step 1370). The cable headend then may transmit episode Aon frequency X and PID Y (step 1380), the terminal 950 then receivingepisode A by accessing frequency X and PID Y (step 1390).

Although flow chart 1300 is shown as a sequence of events, one or moreof the operations may be performed concurrently or in an alternateorder. For example, the terminal 950 may access frequency X and PID Y(step 1390) before or concurrent with the media switch 930 interfacingwith the cable headend 940 (steps 1370 and 1380).

Although the media switch 930 and the cable headend 940 are described inthe context of network operations, the media switch 930, the cableheadend 940, and/or the terminal 950 may use one or more proxy signalsor messages instead of network packets to negotiate the transmission ofthe personal channel. For example, the cable headend 940 may act as abridge between IP commands and cable system commands used to communicatewith the terminal 950.

Other implementations are within the scope of the following claims. Forexample, the media switch 930 may relate the content request toavailable resources. Typically, relating the content request toavailable resources includes determining whether the piece of contentrequested is already being hosted on existing resources. For example, auser may request the same movie that another user has requested. Thetransmission of the movie may be coordinated so that the users may sharethe same resource (e.g., frequency/PID pair). In support of this, alonger series of trailers may be transmitted so that multiple users mayaccess the same resource without missing the featured content.

Another example of relating the content to available resources mayinclude determining the state of demand for resources so that allocationof the frequency/PID pairs accommodates the largest number of usersand/or the priorities of the cable provider. For example, a cableprovider may determine that utilization is approaching the systemcapacity. As a result, some resources, such as Internet access channels,may be reallocated to accommodate premium access channels.

The media switch 930 may determine if the existing resources (e.g.,existing content being transmitted) may be used to enable access to thecontent requested. If so, the media switch 930 transmits accessinformation for the existing resource to the terminal (e.g.,frequency/PID pair already providing the content). If not, the mediaswitch 930 transmits the content to the cable headend 940. The cableheadend 950 receives the content and maps the content into theprescribed access information.

The media switch 930 may include a controller structured and arranged toaccommodate changing cable system architectures. For example, the mediaswitch 930 may include a broadcasting switch and a schedulingcontroller, while other on-demand servers provide on-demand content. Thescheduling controller may interface with these on-demand servers todirect content to the cable headend 940. In one instance, the schedulingcontroller may interface with off-device on-demand content to map it tothe access information.

Although operations have, been described in the context of a pausefunction, similar functionality such as fast forward, rewind, and stopoperations may be implemented. Other operations may include, but are notlimited to, track selection so that a particular program may be advancedprogram-by-program by selecting an icon or figure to advance to the nextpiece of content, e.g., the next show on television. Although it hasbeen described in the context of a cable system, implementations of acable system may include fiber (optical), and/or wireless links. Forexample, a wireless local loop may be used to distribute video contentto one or more users. Alternatively, fiber may be distributed to auser's home for distribution.

Although the media switch and the headend have been described in thecontext of different systems, the media switch and the headend may becombined in one or more systems. This system may include broadcast andon-demand functionality. Indeed, depending on the timing constraints inthe system configuration, the broadcast switch and the on-demand switchmay be the same system. For example, a broadcast switch may include aswitch with a very short buffer designed to keep content that is beingtransmitted within a narrow window of time. In contrast, an on-demandswitch may be configured to store content configured to correspond to alarge period of time.

What is claimed is:
 1. A method of providing multimedia content to aterminal device, the method comprising the following operationsperformed by one or more processors: reserving a personal channel over anetwork to distribute multimedia content to a terminal device, thepersonal channel being available for use by the terminal device for aperiod of time corresponding to a length of the multimedia content;transmitting, from a media switch to the terminal device, reusableaccess information associated with the personal channel to enable theterminal device to access the multimedia content from a network headend;transmitting, from the media switch to the network headend, themultimedia content for transmission to the terminal device as a feed onthe personal channel; detecting a user command altering playback of themultimedia content; and responding to the detected user command based onscheduling of the multimedia content.
 2. The method of claim 1, whereinthe reusable access information includes a process identificationnumber.
 3. The method of claim 1, wherein the reusable accessinformation identifies a baseband frequency and a channel pairing. 4.The method of claim 3, wherein the transmitting is performed bymultiplexing the channel on the baseband frequency.
 5. The method ofclaim 1, wherein the network headend interfaces with the media switch bydetermining a mapping of content into the personal channel as afrequency or PID pair.
 6. The method of claim 1, wherein the networkheadend interfaces with the media switch by accessing a configurationdatabase describing the frequency or content mapping.
 7. The method ofclaim 1, wherein the network headend interfaces with the media switch bymanaging reception of an IP stream or other transport stream with therequested content.
 8. An apparatus, comprising: a storage device thatstores a set of instructions; and at least one processor coupled to thestorage device, the set of instructions configuring the at least oneprocessor to: reserve a personal channel over a network to distributemultimedia content to a terminal device, the personal channel beingavailable for use by the terminal device for a period of timecorresponding to a length of the multimedia content; transmit, from amedia switch to the terminal device, reusable access informationassociated with the personal channel to enable the terminal device toaccess the multimedia content from a network headend; transmit, from themedia switch to the network headend, the multimedia content fortransmission to the terminal device as a feed on the personal channel;detect a user command altering playback of the multimedia content; andrespond to the detected user command based on scheduling of themultimedia content.
 9. The apparatus of claim 8, wherein the reusableaccess information includes a process identification number.
 10. Theapparatus of claim 8, wherein the reusable access information identifiesa baseband frequency and a channel pairing.
 11. The apparatus of claim10, wherein the at least one processor transmits at least one of thereusable access information or multimedia content by multiplexing thechannel on the baseband frequency.
 12. The apparatus of claim 8, whereinthe network headend interfaces with the media switch by determining amapping of content into the personal channel as a frequency or PID pair.13. The apparatus of claim 8, wherein the network headend interfaceswith the media switch by accessing a configuration database describingthe frequency or content mapping.
 14. The apparatus of claim 8, whereinthe network headend interfaces with the media switch by managingreception of an IP stream or other transport stream with the requestedcontent.
 15. A non-transitory computer-readable medium that storesinstructions that, when executed by at least one processor, cause the atleast one processor to perform operations comprising: reserving apersonal channel over a network to distribute multimedia content to aterminal device, the personal channel being available for use by theterminal device for a period of time corresponding to a length of themultimedia content; transmitting, from a media switch to the terminaldevice, reusable access information associated with the personal channelto enable the terminal device to access the multimedia content from anetwork headend; transmitting, from the media switch to the networkheadend, the multimedia content for transmission to the terminal deviceas a feed on the personal channel; detecting a user command alteringplayback of the multimedia content; and responding to the detected usercommand based on scheduling of the multimedia content.
 16. The medium ofclaim 15, wherein the reusable access information includes a processidentification number.
 17. The medium of claim 15, wherein the reusableaccess information identifies a baseband frequency and a channelpairing.
 18. The medium of claim 15, wherein the network headendinterfaces with the media switch by determining a mapping of contentinto the personal channel as a frequency or PID pair.
 19. The medium ofclaim 15, wherein the network headend interfaces with the media switchby accessing a configuration database describing the frequency orcontent mapping.
 20. The medium of claim 15, wherein the network headendinterfaces with the media switch by managing reception of an IP streamor other transport stream with the requested content.